JP5950058B2 - Antioxidant for liquid crystal composition, liquid crystal composition, and liquid crystal display device using the same - Google Patents

Description

  The present invention relates to an antioxidant for a liquid crystal composition useful as a liquid crystal display material, a nematic liquid crystal composition having a positive dielectric anisotropy (Δε), and a liquid crystal display device using the same.

  Liquid crystal display elements are used in various measuring instruments, automobile panels, word processors, electronic notebooks, printers, computers, televisions, watches, advertisement display boards, as well as watches and calculators. Typical liquid crystal display methods include TN (twisted nematic) type, STN (super twisted nematic) type, vertical alignment type using TFT (thin film transistor), and IPS (in-plane switching) type. Alternatively, there are horizontal orientation types such as FFS (fringe field switching) type. The liquid crystal composition used in these liquid crystal display elements is stable against external stimuli such as moisture, air, heat, light, etc., and exhibits a liquid crystal phase in the widest possible temperature range centering on room temperature. And a low driving voltage is required. Furthermore, the liquid crystal composition is composed of several to several tens of kinds of compounds in order to optimize the dielectric anisotropy (Δε) or the refractive index anisotropy (Δn) for each display element. .

  In a vertical alignment (VA) type display, a liquid crystal composition having a negative Δε is used, and in a horizontal alignment type display such as a TN type, STN type, or IPS (in-plane switching) type, a liquid crystal composition having a positive Δε. Is used. In addition, a driving method has been reported in which a liquid crystal composition having a positive Δε is vertically aligned when no voltage is applied and a horizontal electric field is applied to display the liquid crystal composition, and the necessity of a liquid crystal composition having a positive Δε is further increased. Yes. On the other hand, low voltage driving, high-speed response, and a wide operating temperature range are required in all driving systems. That is, Δε is positive, the absolute value is large, the viscosity (η) is small, and a high nematic phase-isotropic liquid phase transition temperature (Tni) is required. Further, from the setting of Δn × d, which is the product of Δn and the cell gap (d), it is necessary to adjust Δn of the liquid crystal composition to an appropriate range according to the cell gap. In addition, when applying a liquid crystal display element to a television or the like, since high-speed response is important, a liquid crystal composition having a low rotational viscosity (γ1) is required.

Examples of the structure of the liquid crystal composition aimed at high-speed response include, for example, a compound represented by the formula (A-1) or (A-2) in which Δε is a positive liquid crystal compound, and a liquid crystal compound in which Δε is neutral. A liquid crystal composition using a combination of (B) is disclosed. The characteristics of these liquid crystal compositions are widely known in the field of liquid crystal compositions that a liquid crystal compound having a positive Δε has a —CF ₂ O— structure and that a liquid crystal compound having a negative Δε has an alkenyl group. It has been. (Patent Documents 1 to 4)

  Further, for example, as shown in Patent Document 5, it is intended to prevent a decrease in specific resistance due to heating in the atmosphere and to maintain a large voltage holding ratio in the vicinity of the upper limit temperature of the nematic phase after a long-time operation of the liquid crystal display element. In general, an antioxidant is mixed in the liquid crystal composition.

JP 2008-037918 A JP 2008-038018 A JP 2010-275390 A JP 2011-052120 A JP 2013-173915 A

  The liquid crystal compositions of Patent Documents 1 to 5 have a high upper limit temperature of the nematic phase, a lower lower limit temperature of the nematic phase, a small viscosity, a large optical anisotropy, a large dielectric anisotropy, a large specific resistance, and a high stability to ultraviolet rays. And at least one characteristic such as high stability against heat.

  However, due to the expansion of applications of liquid crystal display elements in recent years, there has been a great change in usage and manufacturing methods, and it is required to optimize characteristics other than the above-mentioned basic characteristics as conventionally known. It became so. That is, liquid crystal display elements such as VA type and IPS type have been widely used, and super large size display elements having a size of 50 or more have come into practical use. Along with the increase in the substrate size of such a liquid crystal display element, an injection method (ODF: One Drop Fill) has become the main injection method from the conventional vacuum injection method to the injection method of the liquid crystal composition into the substrate. The problem that the drop marks when the liquid crystal composition is dropped on the substrate causes the display quality to deteriorate is brought to the surface. Furthermore, in the liquid crystal display element manufacturing process by the ODF method, it is necessary to drop an optimal liquid crystal injection amount according to the size of the liquid crystal display element. Therefore, when the deviation of the liquid crystal injection amount increases from the optimum value, the balance between the refractive index and the driving electric field of the liquid crystal display element designed in advance is lost, and display defects such as spots and poor contrast occur. In particular, small liquid crystal display elements that are frequently used in smartphones that have become popular recently are difficult to control the deviation from the optimum value within a certain range because the optimum liquid crystal injection amount is small. Therefore, in order to keep the yield of the liquid crystal display element high, for example, there is little influence on the sudden pressure change and impact in the dropping device that occurs when dropping the liquid crystal, and the ability to keep dropping the liquid crystal stably for a long time Is also necessary.

  Thus, in the liquid crystal composition used for the active matrix drive liquid crystal display element driven by a TFT element or the like, while maintaining the characteristics and performance required for a liquid crystal display element such as high-speed response performance, In addition to the characteristics of having a high specific resistance value or high voltage holding ratio, which are emphasized, and being stable against external stimuli such as light and heat, development in consideration of the manufacturing method of liquid crystal display elements has been required. ing. Therefore, the antioxidant added to such a liquid crystal composition is also required to maintain the characteristics of the liquid crystal composition.

  However, the ionic impurities derived from the antioxidant present in the liquid crystal layer of the liquid crystal display element not only cause a decrease in the voltage holding ratio, but also the ionic impurities along the electric field formed in the liquid crystal layer. Due to the planar movement, there is a new problem that ionic impurities derived from the antioxidant are accumulated in a specific portion (hot spot) such as the vicinity of the electrode, and this accumulated region is visually recognized as a (line) afterimage from the outside. It has been confirmed that this occurs.

  Therefore, the present invention solves such problems and is an antioxidant used in a liquid crystal composition having a positive dielectric anisotropy (Δε), has a liquid crystal phase in a wide temperature range, has a low viscosity, An object of the present invention is to provide an antioxidant having good solubility at low temperature, high specific resistance and voltage holding ratio, or maintaining the characteristics of a liquid crystal composition stable against heat and light, and a liquid crystal composition containing the same. . Further, by using this, a liquid crystal display element such as a TN type, an IPS type, or an FFS type, which has excellent display quality and hardly causes display defects such as image sticking and dropping marks, is provided with a high yield.

  The inventor has studied various liquid crystal compounds and various chemical substances, found that the above problems can be solved, and completed the present invention.

An antioxidant for a liquid crystal composition used in a nematic liquid crystal composition containing 3% or more of one or more liquid crystal compounds having a positive dielectric anisotropy having an absolute value of 4 or more,
Formula (II-1)

(Wherein, ^{M y} is one or two or more -CH ₂ in the hydrocarbon (hydrocarbon of 1 to 25 carbon atoms - so as not to directly adjacent is an oxygen atom, -O -, - CO- , -COO-, or -OCO- may be substituted.), Represents a 1,4-phenylene group or a trans-1,4-cyclohexylene group, and an arbitrary hydrogen atom is fluorine. X ^y may be the same or different from each other, and an alkylene group having 1 to 15 carbon atoms (one or more —CH ₂ — in the alkylene group is as the oxygen atoms are not directly adjacent, -O -, - CO -, - COO -, - OCO- may be substituted _{in), -. OCH 2 -,} - CH 2 O -, - COO -, - _{OCO -, - CF 2 O -} , - OCF 2 -, - CF 2 CF 2 -, - H═CH—COO—, —CH═CH—OCO—, —COO—CH═CH—, —OCO—CH═CH—, —CH═CH—, —C≡C—, single bond, 1,4- Represents a phenylene group or a trans-1,4-cyclohexylene group, and the 1,4-phenylene group may have an arbitrary hydrogen atom substituted by a fluorine atom, and l represents an integer of 2 to 6. An antioxidant for a liquid crystal composition and a liquid crystal composition containing the same are provided, and a liquid crystal display device using the same is provided.

  The antioxidant for liquid crystal compositions according to the present invention can maintain the solubility of the entire liquid crystal composition at a low temperature even when mixed with a liquid crystal compound.

  The liquid crystal composition according to the present invention can obtain a very low viscosity or rotational viscosity, good solubility at low temperature, high specific resistance and high voltage holding ratio, and very little change due to heat and light, The practicality of the product is high, and a liquid crystal display element such as a TN type or an IPS type using the product can achieve a high-speed response, and display defects such as a drop mark and a line afterimage are suppressed, which is very useful.

FIG. 1 is a diagram schematically showing a configuration of a liquid crystal display element according to the present invention. FIG. 2 is an enlarged plan view of the region II of the electrode layer including the thin film transistor formed on the substrate in FIG. 3 is a cross-sectional view of the liquid crystal display element shown in FIG. 1 taken along the line III-III in FIG.

The first of the present invention is an antioxidant for a liquid crystal composition used for a liquid crystal composition containing 3% or more of one or more liquid crystal compounds having a positive dielectric anisotropy having an absolute value of 4 or more,
Formula (II-1)

(Wherein, ^{M y} is one or two or more -CH ₂ in the hydrocarbon (hydrocarbon of 1 to 25 carbon atoms - so as not to directly adjacent is an oxygen atom, -O -, - CO- , -COO-, or -OCO- may be substituted.), Represents a 1,4-phenylene group or a trans-1,4-cyclohexylene group, and an arbitrary hydrogen atom is fluorine X ^y may be the same or different from each other, and an alkylene group having 1 to 15 carbon atoms (one or more —CH ₂ — in the alkylene group is as the oxygen atoms are not directly adjacent, -O -, - CO -, - COO -, - OCO- may be substituted _{in), -. OCH 2 -,} - CH 2 O -, - COO -, - _{OCO -, - CF 2 O -} , - OCF 2 -, - CF 2 CF 2 - —CH═CH—COO—, —CH═CH—OCO—, —COO—CH═CH—, —OCO—CH═CH—, —CH═CH—, —C≡C—, single bond, 1,4 -Represents a phenylene group or a trans-1,4-cyclohexylene group, and the 1,4-phenylene group may have an arbitrary hydrogen atom substituted with a fluorine atom, and l represents an integer of 2 to 6. An antioxidant for a liquid crystal composition, characterized by being expressed.

  The antioxidant according to the present invention can maintain the solubility of the entire liquid crystal composition at a low temperature even when mixed with a liquid crystal compound.

  In the antioxidant in this invention, general formula (II-1):

(The above general formula (II-1) in, M ^y is one of the hydrocarbon (hydrocarbon of 1 to 25 carbon atoms or two or more -CH 2 _-, as the oxygen atoms are not directly adjacent , -O-, -CO-, -COO-, and -OCO- may be substituted.), 1,4-phenylene group, trans-1,4-cyclohexylene group, 1,4-phenylene In the group, any hydrogen atom may be substituted by a fluorine atom, X ^y may be the same or different from each other, and an alkylene group having 1 to 15 carbon atoms (one or two in the alkylene group) Two or more —CH ₂ — may be substituted with —O—, —CO—, —COO— or —OCO— so that the oxygen atom is not directly adjacent to each other.), —OCH ₂ —, —CH ₂ O—, —COO—, —OCO—, —CF ₂ O—, —OCF ₂ —, —CF ₂ CF ₂ —, —CH═CH—COO—, —CH═CH—OCO—, —COO—CH═CH—, —OCO—CH═CH—, —CH═CH—, —C≡. C— represents a single bond, a 1,4-phenylene group, or a trans-1,4-cyclohexylene group. In the 1,4-phenylene group, any hydrogen atom may be substituted with a fluorine atom, and l is 2 1 type or 2 types or more are contained.

During the above general formula (II-1), M ^y is one of the hydrocarbon (hydrocarbon having 1 to 10 carbon atoms or two or more -CH 2 _-, as the oxygen atoms are not directly adjacent , -O-, -CO-, -COO-, and -OCO- may be substituted). X ^y represents an alkylene group having 2 to 10 carbon atoms (one or two or more —CH ₂ — in the alkylene group may be —O—, —CO—, -COO- and -OCO- may be substituted.), A single bond, a 1,4-phenylene group or a trans-1,4-cyclohexylene group is preferable. Further, l X ^y in the general formula (II-1) may be the same or different from each other, but are preferably the same. l is preferably an integer of 2 or more and 4 or less, more preferably 2.

  The compound represented by the general formula (II-1) according to the present invention is preferably a compound represented by the following general formula (II-2).

In the general formula (II-2), M ^x is a hydrocarbon having 1 to 25 carbon atoms (one or more —CH ₂ — in the hydrocarbon is- Represents an O-, -CO-, -COO-, or -OCO-, which is a hydrocarbon having 2 to 15 carbon atoms (one or more -CH in the hydrocarbon). _2- is preferably substituted with —O—, —CO—, —COO—, or —OCO— so that oxygen atoms are not directly adjacent to each other.

In the general formula (II-2), each X is independently an alkylene group having 1 to 15 carbon atoms (one or more of —CH ₂ — in the alkylene group is directly adjacent to an oxygen atom) And may be substituted with —O—, —CO—, —COO—, —OCO—), —OCH ₂ —, —CH ₂ O—, —COO—, —OCO—, —CF ₂ O—, —OCF ₂ —, —CF ₂ CF ₂ —, —CH═CH—COO—, —CH═CH—OCO—, —COO—CH═CH—, —OCO—CH═CH—, —CH = CH-, -C≡C-, single bond, 1,4-phenylene group or trans-1,4-cyclohexylene group (any hydrogen atom in 1,4-phenylene group is substituted by fluorine atom) Or an alkylene group having 2 to 15 carbon atoms (the alkylene group). One or two or more -CH ₂ in the group - is, as the oxygen atoms are not directly adjacent, -O -, - CO -, - COO -, - OCO- may be substituted in). A single bond, 1,4-phenylene group or trans-1,4-cyclohexylene group is preferred. The four Xs in the general formula (II-2) may be the same or different from each other, but are preferably the same. l is preferably an integer of 2 or more and 4 or less, more preferably 2.

  In the general formula (II-2), a, b, c and d each independently represent 0 or 1, but a + b + c + d represents 2 or more. a + b + c + d is more preferably 2 to 4, and more preferably 2.

  The antioxidant represented by the general formula (II-1) according to the present invention is preferably a hindered phenol derivative represented by the following general formula (II).

In the above general formula (II), M is an alkylene group having 1 to 15 carbon atoms (one or two or more —CH ₂ — in the alkylene group is —O— , -CO -, - COO -, - OCO- may be substituted _{in), -. OCH 2 -,} - CH 2 O -, - COO -, - OCO -, - CF 2 O -, - OCF 2 —, —CF ₂ CF ₂ —, —CH═CH—COO—, —CH═CH—OCO—, —COO—CH═CH—, —OCO—CH═CH—, —CH═CH—, —C≡. Although it represents C-, a single bond, a 1,4-phenylene group or a trans-1,4-cyclohexylene group (any hydrogen atom in the 1,4-phenylene group may be substituted with a fluorine atom). , Preferably an alkylene group having 1 to 14 carbon atoms, and volatile In consideration of the viscosity, it is preferable that the number of carbon atoms is large. However, since it is preferable that the number of carbon atoms is not too large in consideration of the viscosity, M in the general formula (II) according to the present invention further includes 2 to 12 carbon atoms. Preferably, it has 3 to 10 carbon atoms, more preferably 4 to 10 carbon atoms, still more preferably 5 to 10 carbon atoms, and still more preferably 6 to 10 carbon atoms.

  The antioxidant according to the present invention is a compound represented by the following formula (II-a6), formula (II-a7), formula (II-a8), formula (II-a9) or formula (II-a10). Is particularly preferred.

  The antioxidant according to the present invention preferably coexists with a liquid crystal compound, and more preferably coexists with a nematic liquid crystal compound (or a nematic liquid crystal composition). In this case, the liquid crystal composition preferably contains one or more antioxidants, and the content is preferably 0.001 to 1% by mass, and 0.001 to 0.5% by mass. More preferred is 0.01 to 0.3% by mass.

  The liquid crystal composition according to the present invention contains one or more liquid crystal compounds having a positive dielectric anisotropy having an absolute value of 4 or more, and the content of the liquid crystal compound is 3% by mass. Although it is above, it is preferably 5% by mass or more, more preferably 10% by mass or more, and particularly preferably 20% by mass or more. More specifically, it is preferably 3% by mass to 70% by mass, more preferably 5% by mass to 60% by mass, further preferably 10% by mass to 60% by mass, and more preferably 20% by mass. It is especially preferable that it is 60 mass%. Note that the dielectric anisotropy of the liquid crystal compound represents a value at 20 ° C. The “liquid crystal composition” in the present specification is a composition containing a liquid crystal compound having a positive dielectric anisotropy having an absolute value of 4 or more and the antioxidant according to the present invention.

The liquid crystal composition according to the present invention includes the antioxidant according to the present invention (including compounds represented by general formula (II-1), general formula (II-2), and general formula (II));
General formula (N1):

(In the general formula (N1), R ⁿ¹ represents an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, and one or non-adjacent two or more —CH in the group. ₂ - each independently, -C≡C -, - O -, - CO -, - COO- or may be substituted by -OCO-, 1 one or non-adjacent two or more in the group Each hydrogen atom may be independently substituted with a fluorine atom,
Ring N ¹ is a 1,4-cyclohexylene group (one or two or more non-adjacent —CH ₂ — in the group may be substituted by —O— or —S—) or 1, Represents a 4-phenylene group (one or two or more non-adjacent —CH═ in the group may be substituted by —N═), and each hydrogen atom in the group independently represents a cyano group. , May be substituted with a fluorine atom,
Z ⁿ¹ and Z ⁿ² are each independently a single bond, —CH ₂ CH ₂ —, — (CH ₂ ) ₄ —, —OCH ₂ —, —CH ₂ O—, —OCF ₂ —, —CF ₂ O. _{-, - CH 2 CH 2 CF} 2 O -, - COO -, - OCO- or -C≡C- represent,
n ⁿ¹ each independently represents an integer of 0 to 4, and when n ⁿ¹ is 2 or more, ring N ¹ may be the same or different, and when n ⁿ¹ is 1 or more, Z ⁿ¹ is Can be the same or different,
X ⁿ¹ , X ⁿ² , X ⁿ³ , X ⁿ⁴ and X ⁿ⁵ each independently represent a hydrogen atom or a fluorine atom,
Y ⁿ¹ each independently represents a fluorine atom, a cyano group, a trifluoromethyl group, a fluoromethoxy group, a difluoromethoxy group, a trifluoromethoxy group or a 2,2,2-trifluoroethyl group, A trifluoromethyl group, a fluoromethoxy group, a difluoromethoxy group or a trifluoromethoxy group is represented. It is preferable to contain 1 type, or 2 or more types of compounds represented by this.

  By combining a specific liquid crystal compound and a specific antioxidant, display defects such as dripping marks and line afterimages are suppressed, and low viscosity or low rotational viscosity, low temperature solubility or high specific resistance and voltage holding ratio, A liquid crystal composition excellent in light resistance or heat resistance can be provided.

  The liquid crystal composition containing the compound represented by the general formula (N1) and the antioxidant contained in the liquid crystal composition according to the present invention maintains high refractive index anisotropy (Δn) and is excellent in reliability. This is preferable.

  Further, the compound represented by the general formula (N1) contained in the liquid crystal composition according to the present invention is preferably a liquid crystal compound having a positive dielectric anisotropy having an absolute value of 4 or more. More preferably, it is a liquid crystal compound having a positive dielectric anisotropy having a value of 5 or more, more preferably a liquid crystal compound having a positive dielectric anisotropy having an absolute value of 6 or more. A liquid crystal compound having a positive dielectric anisotropy having a value of 7 or more is more preferable, a liquid crystal compound having a positive dielectric anisotropy having an absolute value of 8 or more is more preferable, and an absolute More preferably, it is a liquid crystal compound having a positive dielectric anisotropy having a value of 9 or more, more preferably a liquid crystal compound having a positive dielectric anisotropy having an absolute value of 10 or more. Positive dielectric constant with a value of 15 or more The liquid crystal compound is more preferably a liquid crystal compound having a positive polarity, more preferably a liquid crystal compound having a positive dielectric anisotropy having an absolute value of 20 or more, and a positive dielectric constant anisotropy having an absolute value of 25 or more. The upper limit of the positive dielectric anisotropy is preferably 50 or less, more preferably 45 or less, and even more preferably 40 or less.

  In the liquid crystal composition according to the present invention, the content of the compound represented by the general formula (N1) is preferably 1 to 50% by mass, more preferably 2 to 45% by mass, and 3 to 40% by mass. % Is further preferable, 5 to 35% by mass is even more preferable, and 10 to 30% by mass is particularly preferable.

  In the liquid crystal composition according to the present invention, the compound represented by the general formula (N1) is contained in one or more types, preferably 1 to 10 types, and preferably 1 to 9 types. More preferably, it is more preferably 1 to 8 types, and even more preferably 1 to 7 types.

  The compound represented by the general formula (N1) according to the present invention is preferably a compound selected from the group consisting of compounds represented by the general formulas (N1-1) and (N1-2). It is more preferable that it is a compound represented by N1-2).

(The above general formula (N1-1) and the general formula ^{(N1-2), R n1, X} n1, X n2, X n3, X n4, X n5, Y n1, n n1 and ^{Z n1} is as previously described And ring N ¹ is 1,4-cyclohexylene group, tetrahydropyran-2,5-diyl group, 1,4-phenylene group, 3-fluoro-1,4-phenylene group or 3,5-difluoro- Represents a 1,4-phenylene group or a dioxane group.)
In the liquid crystal composition according to the present invention, the content of the compound represented by the general formula (N1-1) is preferably 1 to 50% by mass, more preferably 2 to 45% by mass, and 3 to It is more preferably 40% by mass, still more preferably 4 to 35% by mass, and particularly preferably 10 to 30% by mass.

  In the liquid crystal composition according to the present invention, the content of the compound represented by the general formula (N1-2) is preferably 1 to 50% by mass, more preferably 2 to 45% by mass, and 3 to It is more preferably 40% by mass, still more preferably 4 to 35% by mass, and particularly preferably 10 to 30% by mass.

  The compound represented by the general formula (N1) according to the present invention is more preferably the following general formula (N3).

(In the general formula (N3), R ⁿ¹ , X ⁿ¹ , X ⁿ² , X ⁿ⁴ , X ⁿ⁵ and Y ⁿ¹ are as described above, and X ¹ and X ² are each independently a hydrogen atom or a fluorine atom. Represents
Ring N ¹ is 1,4-cyclohexylene group, tetrahydropyran-2,5-diyl group, 1,4-phenylene group, 3-fluoro-1,4-phenylene group or 3,5-difluoro-1,4. -Represents a phenylene group or a dioxane group, and n is an integer of 0 or more and 2 or less. )
In the liquid crystal composition according to the present invention, the content of the compound represented by the general formula (N3) is preferably 1 to 50% by mass, more preferably 2 to 45% by mass, and 3 to 40% by mass. % Is more preferable, 4 to 35% by mass is even more preferable, and 10 to 30% by mass is particularly preferable.

  As the compound represented by the general formula (N3) according to the present invention, the following (N3-1) to (N3-) are preferable.

  In the liquid crystal composition according to the present invention, the content of each of the compounds represented by the general formula (N3-1) to the general formula (N3-4) is preferably 0.01 to 15% by mass. It is more preferably 1 to 12% by mass, and further preferably 0.5 to 10% by mass.

  The liquid crystal composition according to the present invention preferably contains a compound represented by the general formula (K).

(In the general formula (K), each R ^k1 independently represents an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, and one or non-adjacent 2 in the group) _Two or more —CH ₂ — may each independently be substituted by —C≡C—, —O—, —CO—, —COO— or —OCO—, one or non-adjacent in the group In which two or more hydrogen atoms may be independently substituted with fluorine atoms,
Ring K ¹ and Ring K ² are each independently a 1,4-cyclohexylene group (one or two or more non-adjacent —CH ₂ — in the group is substituted by —O— or —S—). Or a 1,4-phenylene group (one or two or more non-adjacent —CH═ in the group may be substituted by —N═), and hydrogen in the group Each atom may be independently substituted with a cyano group, a fluorine atom or a chlorine atom,
Ring K ⁰ represents a naphthalene-2,6-diyl group or a 1,4-phenylene group, and each hydrogen atom in the group may be independently substituted with a fluorine atom,
Z ^k1 , Z ^k2 and Z ^k3 are each independently a single bond, —CH ₂ CH ₂ —, — (CH ₂ ) ₄ —, —OCH ₂ —, —CH ₂ O—, —OCF ₂ —, — CF ₂ O—, —CH ₂ CH ₂ CF ₂ O—, —COO—, —OCO— or —C≡C— represents a single bond, —CH ₂ CH ₂ —, —OCH ₂ —, —CH _2. O -, - OCF ₂ - or _-CF 2 O-are more preferred.

n ^k1 independently represents 0, 1, 2, 3 or 4, and when n ^k1 is 2 or more, the rings K ² may be the same or different,
X ^k1 , X ^k2 , X ^k3 and X ^k4 each independently represent a hydrogen atom or a fluorine atom, and Y ^k1 represents a fluorine atom, a cyano group, a trifluoromethyl group, a fluoromethoxy group, a difluoromethoxy group, a trifluoromethoxy group, A fluoromethoxy group or a 2,2,2-trifluoroethyl group is represented by a fluorine atom, a trifluoromethyl group, a fluoromethoxy group, a difluoromethoxy group or a trifluoromethoxy group. )
In the liquid crystal composition according to the invention, the content of the compound represented by the general formula (K) is preferably 0 to 30% by mass, more preferably 1 to 20% by mass, and 3 to 20% by mass. % Is more preferable, and it is still more preferable that it is 3 to 15 mass%.

  In the liquid crystal composition according to the present invention, when the compound represented by the general formula (K) is added, it is contained in one or more types, preferably 1 to 10 types, and preferably 1 to 8 types. It is more preferable that 1 to 6 types are contained, and 1 to 3 types are more preferably contained.

  The compound represented by the general formula (K) is preferably a compound represented by the following general formula (K1).

(In the general formula (K1), R ^k1 , ring K ¹ , ring K ² , n ^k1 , X ^k1 , X ^k2 , X ^k3 , X ^k4 , Y ^k1 , Z ^k1 , Z ^k2, and Z ^k3 are (It is omitted here because it is as in general formula (K).)
In the liquid crystal composition according to the present invention, the content of the compound represented by the general formula (K1) is preferably 0 to 30% by mass, more preferably 1 to 20% by mass, and 3 to 20% by mass. % Is more preferable, and it is still more preferable that it is 3 to 15 mass%.

  The compound represented by the general formula (K1) according to the present invention is preferably a compound selected from the group of compounds represented by the following general formulas (K11) to (K24), from the general formula (K11) to ( More preferred is a compound selected from the group of compounds represented by K17).

(In the above general formulas (K11) to (K24), R ^k1 , ring K ² , Z ^k2 , Z ^k3 , n ^k1 , X ^k1 , X ^k2 , X ^k3 , X ^k4 and Y ^k1 are as described above. .)
The compound represented by the general formula (K) is preferably a compound represented by the following general formula (K2).

(In the general formula (K2), R ^k1 , ring K ¹ , ring K ² , n ^k1 , X ^k1 , X ^k2 , X ^k3 , X ^k4 , Y ^k1 , Z ^k1 , Z ^k2, and Z ^k3 are the same as those described above. (It is omitted here because it is as in general formula (K).)
In the liquid crystal composition according to the present invention, the content of the compound represented by the general formula (K2) is preferably 0 to 30% by mass, more preferably 1 to 20% by mass, and 3 to 20% by mass. % Is more preferable, and it is still more preferable that it is 3 to 15 mass%.

  The compound represented by the general formula (K2) according to the present invention is preferably a compound selected from the group of compounds represented by the following general formulas (K25) to (K28), from the general formula (K25) to ( More preferred is a compound selected from the group of compounds represented by K26).

  In the liquid crystal composition according to the present invention, the content of each of the compounds represented by the general formulas (K25) to (K28) is preferably 0 to 15% by mass, and 0.01 to 12% by mass. More preferred is 0.5 to 10% by weight.

  The liquid crystal compound having a positive dielectric anisotropy and having an absolute value of 4 or more contained in the liquid crystal composition of the present invention is also preferably a general formula (Pa).

In the general formula (Pa), R ^Nc1 represents an alkyl group having 1 to 8 carbon atoms or an alkenyl group having 2 to 8 carbon atoms, and one or two or more non-adjacent —CH ₂ — in the group. Each independently may be substituted by —C≡C—, —O—, —CO—, —COO— or —OCO—, but may be an alkyl group having 1 to 5 carbon atoms or 2 carbon atoms. ˜5 alkenyl groups are preferred.

In the general formula (Pa), the rings P ¹ , P ² and P ³ are each independently a 1,4-cyclohexylene group (one in the group or two or more non-adjacent —CH ₂ — is — May be substituted by O- or -S-) or a 1,4-phenylene group (one or two or more non-adjacent -CH = in the group may be substituted by -N =). ), Each hydrogen atom in the group may be independently substituted with a cyano group, a fluorine atom or a chlorine atom, but a 1,4-cyclohexylene group, a tetrahydropyran-2,5-diyl group, A 1,4-phenylene group, a 3-fluoro-1,4-phenylene group or a 3,5-difluoro-1,4-phenylene group is preferred.

In the above general formula (Pa), Z ^Nc1 , Z ^Nc2 or Z ^Nc3 are each independently a single bond, —CH ₂ CH ₂ —, — (CH ₂ ) ₄ —, —OCH ₂ —, —CH ₂ O. _{-, - OCF 2 -, -} CF 2 O -, - COO -, - OCO- or -C≡C- represents a single _{bond, -CH 2 CH 2 -, -} CH 2 O- or _-CF 2 O ^-Is more preferred, and any one of Z ^Nc1 , Z ^Nc2 or Z ^Nc3 present is more preferably a single bond.

In the general formula (Pa), n ^c1 , n ^c2 or n ^c3 each independently represents 0, 1 or 2. n ^c1 + n ^c2 + n ^c3 represents 1 to 5, more preferably 4 or less, and particularly preferably 3 or less.

In the general formula (Pa), X ^Nc1 and X ^Nc2 each independently represent a hydrogen atom or a fluorine atom.

In the general formula (Pa), Y ^Nc1 represents a fluorine atom, a chlorine atom, a cyano group, a trifluoromethyl group, a fluoromethoxy group, a difluoromethoxy group, a trifluoromethoxy group, or a 2,2,2-trifluoroethyl group. It is preferably a fluorine atom, a trifluoromethyl group, a fluoromethoxy group, a difluoromethoxy group or a trifluoromethoxy group, and more preferably a fluorine atom, a trifluoromethyl group or a trifluoromethoxy group.

  In the liquid crystal composition according to the present invention, the content of the compound represented by the general formula (Pa) is preferably 0 to 50% by mass, more preferably 1 to 40% by mass, 30 mass% is further more preferable, it is more preferable that it is 3-30 mass%, and it is still more preferable that it is 5-30 mass%.

  The compound represented by the general formula (Pa) according to the present invention is preferably a compound selected from the group of compounds represented by the general formulas (P01) to (P80).

In the general formulas (P1) to (P80), R ^Nc1 represents an alkyl group having 1 to 8 carbon atoms or an alkenyl group having 2 to 8 carbon atoms, and one or two or more non-adjacent groups in the group Each of —CH ₂ — may be independently substituted by —C≡C—, —O—, —CO—, —COO— or —OCO—, but may be an alkyl group having 1 to 5 carbon atoms. Alternatively, an alkenyl group having 2 to 5 carbon atoms is preferable.

In the general formulas (P1) to (P80), Y ^Nc2 represents a hydrogen atom, a fluorine atom, a chlorine atom, a cyano group, a trifluoromethyl group, a fluoromethoxy group, a difluoromethoxy group, a trifluoromethoxy group, or 2,2. , 2-trifluoroethyl group, preferably a fluorine atom, a trifluoromethyl group, a fluoromethoxy group, a difluoromethoxy group or a trifluoromethoxy group, and a fluorine atom, a trifluoromethyl group or a trifluoromethoxy group. More preferably it is.

  Examples of the compound represented by the general formula (Pa) according to the present invention include the following compounds.

  The liquid crystal composition according to the present invention has a dielectric anisotropy (Δε) of −3 as a third component other than the antioxidant or the liquid crystal compound having a positive dielectric anisotropy having an absolute value of 4 or more. 1 to +1 compounds (preferably having a dielectric anisotropy (Δε) of −0.5 to +0.5) can be contained.

  As said 3rd component, the compound represented by the following general formula (L)

(In the general formula (L), R ^L1 and R ^L2 each independently represent an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, and one of the alkyl groups Or two or more non-adjacent —CH ₂ — may be independently substituted with —CH═CH—, —C≡C—, —O—, —CO—, —COO— or —OCO—. Often,
OL represents 0, 1, 2 or 3;
B ^L1 , B ^L2 and B ^L3 each independently represent (a) a 1,4-cyclohexylene group (one —CH ₂ — present in this group or two or more —CH ₂ — not adjacent to each other). May be replaced by -O-) and (b) 1,4-phenylene group (one -CH = present in this group or two or more non-adjacent -CH = are -N May be replaced by =.)
Represents a group selected from the group consisting of: 1 and / or 2 or more hydrogen atoms in the above groups (a) and (b) are each independently substituted with a cyano group, a fluorine atom or a chlorine atom. You may,
L ^L1 and L ^L2 are each independently a single bond, —CH ₂ CH ₂ —, — (CH ₂ ) ₄ —, —OCH ₂ —, —CH ₂ O—, —COO—, —OCO—, —OCF _2. —, —CF ₂ O—, —CH═N—N═CH—, —CH═CH—, —CF═CF— or —C≡C—,
When OL is 2 or 3 and a plurality of L ^L2 are present, they may be the same or different, and when OL is 2 or 3 and a plurality of B ^L3 is present, they are the same Or different. However, the compound represented by general formula (K), general formula (N1), and general formula (Pa) is excluded. 1) or 2 or more types, preferably 1 to 20 types, more preferably 2 to 10 types.

  The compound represented by General Formula (L) is preferably a compound selected from the group of compounds represented by General Formula (III-A) to General Formula (III-J).

In the general formulas (III-A) to (III-J), R ⁵ is preferably an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms. More preferably, it is a 5 alkyl group or an alkenyl group having 2 to 5 carbon atoms. R ⁶ is preferably an alkyl group having 1 to 10 carbon atoms, an alkoxyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or an alkenyloxy group having 2 to 10 carbon atoms, More preferably, it is an alkyl group having 1 to 5 carbon atoms, an alkoxyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or an alkenyloxy group having 2 to 5 carbon atoms.

  The third component in the liquid crystal composition according to the present invention includes general formula (III-A), general formula (III-D), general formula (III-F), general formula (III-G), and general formula (III- More preferred is a compound selected from H), which is a compound selected from General Formula (III-A), General Formula (III-F), General Formula (III-G), and General Formula (III-H). It is particularly preferred.

In the compounds represented by general formula (III-D), general formula (III-G), and general formula (III-H), R ⁵ represents an alkyl group having 1 to 5 carbon atoms or 2 carbon atoms. To an alkenyl group having 5 to 5 carbon atoms, R ⁶ is preferably an alkyl group having 1 to 5 carbon atoms or an alkoxy group having 1 to 5 carbon atoms. In the compound represented by the general formula (III-F), R ⁵ and R ⁶ are preferably each independently an alkyl group having 1 to 5 carbon atoms or an alkenyl group having 2 to 5 carbon atoms.

  The content of the compound represented by the general formula (L) as the third component is preferably 0 to 20% by mass, more preferably 1 to 20% by mass, and 3 to 20% by mass. More preferably, it is more preferably 3 to 15% by mass.

  As the compound represented by the general formula (L), one or more compounds represented by the general formula (VIII-c) to the general formula (VIII-e) may be contained.

In the formula, R ⁵¹ and R ⁵² are each independently an alkyl group having 1 to 5 carbon atoms, an alkoxyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or 2 to 2 carbon atoms. 5 represents an alkenyloxy group, and X ⁵¹ and X ⁵² each independently represent a fluorine atom, a chlorine atom or a hydrogen atom.

  More specifically, a compound of formula (V-6.1) can be mentioned.

As the compound represented by the general formula (L), one or more compounds represented by the general formula (V-9.1) to the general formula (V-9.3) may be contained.

  An embodiment of the liquid crystal composition according to the present invention includes an antioxidant represented by general formula (II-1), a compound represented by general formula (N1), and a compound represented by general formula (L). The antioxidant represented by general formula (II-1), the compound represented by general formula (N1), the compound represented by general formula (L), and general formula (Pa) The compound represented by general formula (II-1), the compound represented by general formula (N1), the compound represented by general formula (L) And a compound represented by the general formula (Pa) and a compound represented by the general formula (K1) are more preferable. Moreover, as other embodiment, the antioxidant represented by general formula (II-1), the compound represented by general formula (N1-2), and the compound represented by general formula (L) are included. Is preferred.

  In another preferred embodiment of the liquid crystal composition according to the present invention, the antioxidant represented by the general formula (II-1), the compound represented by the general formula (N1) and / or the general formula (K) The compound represented by the general formula (II-1), the compound represented by the general formula (N1), and / or the general formula (II-1). It includes at least one compound represented by formula (K) and at least one compound represented by formula (L). In another preferred embodiment of the liquid crystal composition according to the present invention, an antioxidant represented by the general formula (II-1) and at least one compound represented by the general formula (N1) And at least one compound represented by the general formula (K2) and at least one compound represented by the general formula (L).

  The liquid crystal composition of the present invention has a dielectric anisotropy (Δε) at 20 ° C. of 2.0 to 20.0, preferably 2.0 to 18.0, and more preferably 3.0 to 16.0. 4.0 to 16.0 are particularly preferable.

  The liquid crystal composition of the present invention has a refractive index anisotropy (Δn) at 20 ° C. of 0.08 to 0.18, more preferably 0.09 to 0.15, and 0.09 to 0.12. Particularly preferred. More specifically, it is preferably 0.10 to 0.18 when dealing with a thin cell gap, and preferably 0.08 to 0.10 when dealing with a thick cell gap.

The liquid crystal composition of the present invention has a nematic phase-isotropic liquid phase transition temperature (T _ni ) of 60 ° C to 120 ° C, more preferably 70 ° C to 110 ° C, and particularly preferably 70 ° C to 100 ° C.

  The liquid crystal composition of the present invention has a viscosity (η) at 20 ° C. of 10 to 30 mPa · s, more preferably 10 to 25 mPa · s, and particularly preferably 10 to 20 mPa · s.

The liquid crystal composition of the present invention has a rotational viscosity (γ ₁ ) at 20 ° C. of 50 to 130 mPa · s, more preferably 50 to 110 mPa · s, and particularly preferably 50 to 90 mPa · s. .

  The liquid crystal composition according to the present invention may contain a polymerizable compound in order to produce a liquid crystal display element such as a PS mode, a lateral electric field type PSA mode, or a lateral electric field type PSVA mode. Examples of the polymerizable compound that can be used include a photopolymerizable monomer having a liquid crystal skeleton in which a plurality of six-membered rings are connected, such as a biphenyl derivative and a terphenyl derivative that are polymerized by energy rays such as light. For example, it is preferable to contain 0.01 to 2% by mass of a polymerizable compound such as a biphenyl derivative or a terphenyl derivative as a polymerizable monomer. More specifically, the liquid crystal composition of the present invention has the general formula (M).

1 type or 2 types or more of the polymeric compound represented by these are contained.

In General Formula (M), X ²⁰¹ and X ²⁰² each independently represent a hydrogen atom, a methyl group, or a —CF ₃ group. X ²⁰¹ and X ²⁰² are each preferably a diacrylate derivative that is a hydrogen atom, and a dimethacrylate derivative that is both a methyl group, and a compound in which one is a hydrogen atom and the other is a methyl group. A preferred compound can be used depending on the application, but in the PSA display element, the polymerizable compound represented by the general formula (M) preferably has at least one methacrylate derivative, and preferably has two.

Sp ²⁰¹ and Sp ²⁰² are each independently a single bond, an alkylene group having 1 to 8 carbon atoms, or —O— (CH ₂ ) _s — (wherein _s represents an integer of 2 to 7, Represents a bond to a ring). In the PSA mode liquid crystal display element, at least one of Sp ²⁰¹ and Sp ²⁰² is preferably a single bond, both of which are single bonds or one of which is a single bond and the other is an alkylene having 1 to 8 carbon atoms. It is preferably a group or —O— (CH ₂ ) _s —. In this case, an alkylene group having 1 to 4 carbon atoms is preferred, and s is preferably 1 to 4.

Ring M ²⁰¹ , Ring M ²⁰² and Ring M ²⁰³ are each independently a trans-1,4-cyclohexylene group (one or two or more non-adjacent —CH ₂ — in the group represents —O— or May be substituted by -S-), 1,4-phenylene group (one or two or more non-adjacent -CH = in the group may be substituted by -N =), 1,4-cyclohexenylene group, 1,4-bicyclo [2.2.2] octylene group, piperidine-1,4-diyl group, naphthalene-2,6-diyl group, decahydronaphthalene-2,6- Represents a diyl group or a 1,2,3,4-tetrahydronaphthalene-2,6-diyl group, and each hydrogen atom in the group is independently a fluorine atom, a —CF ₃ group, or a carbon atom number of 1 to 10. Alkyl group, alkoxyl having 1 to 10 carbon atoms It may be substituted by a group or any of formula (R-1) to formula (R-15).

Z ²⁰¹ and Z ²⁰² each independently represent —OCH ₂ —, —CH ₂ O—, —COO—, —OCO—, —CF ₂ O—, —OCF ₂ —, —CH ₂ CH ₂ —, — CF ₂ CF ₂ —, —CH═CH—COO—, —CH═CH—OCO—, —COO—CH═CH—, —OCO—CH═CH—, —COO—CH ₂ CH ₂ —, —OCO— _{CH 2 CH 2 -, - CH} 2 CH 2 -COO -, - CH 2 CH 2 -OCO -, - COO-CH 2 -, - OCO-CH 2 -, - CH 2 -COO -, - CH 2 -OCO —, —CY ¹ ═CY ² — (wherein Y ¹ and Y ² each independently represents a fluorine atom or a hydrogen atom), —C≡C— or a single bond, —COO— , -OCO-, -CH = CH-COO-, -CH = CH-OCO-, _{COO-CH = CH -, -} OCO-CH = CH -, - COO-CH 2 CH 2 -, - OCO-CH 2 CH 2 -, - CH 2 CH 2 -COO -, - CH 2 CH 2 -OCO- , —C≡C— or a single bond is preferred, —COO—, —OCO—, —CH═CH—COO—, —CH═CH—OCO—, —COO—CH═CH—, —OCO—CH═CH _{-, - COO-CH 2 CH} 2 -, - OCO-CH 2 CH 2 -, - CH 2 CH 2 -COO -, - CH 2 CH 2 -OCO- or a single bond is more preferable.

n ²⁰¹ represents 0, 1 or 2, with 0 or 1 being preferred. However, when there are a plurality of rings M ²⁰² and Z ²⁰² , they may be different or the same.

  The polymerizable compound-containing liquid crystal composition of the present invention contains at least one polymerizable compound represented by formula (M), preferably 1 to 5 types, and preferably 1 to 3 types. More preferably. When there is little content of the polymeric compound represented by general formula (M), the alignment control power with respect to a liquid-crystal composition will become weak. On the contrary, when the content of the polymerizable compound represented by the general formula (M) is too large, the energy required for the polymerization increases, the amount of the polymerizable compound remaining without being polymerized increases, and the display is poor. Therefore, the content is preferably 0.01 to 2.00% by mass, more preferably 0.05 to 1.00% by mass, and 0.10 to 0.50% by mass. It is particularly preferred that

More specifically, when n ²⁰¹ is 0 in the general formula (M), the ring structure between Sp ²⁰¹ and Sp ²⁰² is preferably the formula (XXa-1) to the formula (XXa-5), The formula (XXa-1) to the formula (XXa-3) are more preferable, and the formula (XXa-1) or the formula (XXa-2) is particularly preferable. However, both ends of the equation shall be connected to Sp ²⁰¹ or Sp ²⁰² .

  The polymerizable compound represented by the general formula (M) containing these skeletons is suitable for a PSA mode liquid crystal display element because of its alignment regulating force after polymerization, and a good alignment state can be obtained, thereby suppressing display unevenness. There is an effect that does not occur at all.

  From the above, as the polymerizable monomer, compounds represented by formula (XX-1) to general formula (XX-10) are preferable, and formula (XX-1) to formula (XX-4) are more preferable.

In the formula, Sp ^xx represents an alkylene group having 1 to 8 carbon atoms or —O— (CH ₂ ) _s — (wherein _s represents an integer of 2 to 7, and an oxygen atom is bonded to the ring. ).

The hydrogen atom in the phenyl group in the formula may be further substituted with —F, —Cl, —CF ₃ , —CH ₃ , or any one of the formulas (R-1) to (R-15). .

In the general formula (M), when n ²⁰¹ is 1, for example, a polymerizable compound such as the formula (M31) to the formula (M48) is preferable.

The hydrogen atom in the phenyl group and naphthalene group in the formula is further substituted with —F, —Cl, —CF ₃ , —CH ₃ , or any one of formulas (R-1) to (R-15). May be.

  The polymerizable compound represented by the general formula (M) containing these skeletons is suitable for a PSA mode liquid crystal display element because of its alignment regulating force after polymerization, and a good alignment state can be obtained, thereby suppressing display unevenness. There is an effect that does not occur at all.

In the general formula (M), when n ²⁰¹ is 1 and there are a plurality of formulas (R-1) or (R-2), for example, polymerizable compounds such as formulas (M301) to (M316) preferable.

Hydrogen atom of the phenyl group and in the naphthalene radical in the formula, further, -F, _-Cl, -CF 3, may be substituted by -CH _3.

  As the polymerizable compound represented by Formula (M) according to the present invention, for example, polymerizable compounds such as Formula (Ia-1) to Formula (Ia-31) are also preferable.

  The polymerizable compound represented by the general formula (M) containing these skeletons is suitable for a PSA mode liquid crystal display element because of its alignment regulating force after polymerization, and a good alignment state can be obtained, thereby suppressing display unevenness. There is an effect that does not occur at all.

In the liquid crystal composition according to the present invention, the polymerizable compound-containing liquid crystal composition containing the general formula (M) as the polymerizable compound has a low viscosity (η), a low rotational viscosity (γ ₁ ), and a large elastic constant ( K ₃₃ ) can be obtained, so that a PSA mode or PSVA mode liquid crystal display element using this can achieve a high-speed response.

  The liquid crystal display device using the liquid crystal composition of the present invention has a remarkable feature of high-speed response, and is particularly useful for a liquid crystal display device for active matrix driving, and includes TN mode, VA mode, PSVA mode, PSA. Applicable for mode, IPS mode, FFS mode or ECB mode.

  In the case of adding a polymerizable compound to the liquid crystal composition of the present invention, the polymerization proceeds even when no polymerization initiator is present, but may contain a polymerization initiator in order to accelerate the polymerization. Examples of the polymerization initiator include benzoin ethers, benzophenones, acetophenones, benzyl ketals, acylphosphine oxides, and the like.

  Hereinafter, as a preferred embodiment of the liquid crystal display element according to the present invention, a horizontal electric field type liquid crystal display element will be described with reference to the drawings. However, the liquid crystal display element according to the present invention is not limited thereto.

  FIG. 1 is a diagram schematically showing a configuration of a liquid crystal display element. In FIG. 1, for convenience of explanation, each component is illustrated separately. As shown in FIG. 1, the liquid crystal display element 10 according to the present invention has a liquid crystal composition sandwiched between a first transparent insulating substrate 2 and a second transparent insulating substrate 7 that are arranged to face each other. A liquid crystal display element of a lateral electric field type (an FFS mode as an example in the figure) having an object (or liquid crystal layer 5), characterized in that the liquid crystal composition of the present invention is used as the liquid crystal composition. is there. The first transparent insulating substrate 2 has an electrode layer 3 formed on the surface on the liquid crystal layer 5 side. In addition, a pair of alignments that induce a homogeneous alignment between the liquid crystal layer 5 and the first transparent insulating substrate 2 and the second transparent insulating substrate 8 in direct contact with the liquid crystal composition constituting the liquid crystal layer 5. The film 4 is provided, and the liquid crystal molecules in the liquid crystal composition are aligned so as to be substantially parallel to the substrates 2 and 7 when no voltage is applied. As shown in FIGS. 1 and 3, the second substrate 7 and the first substrate 2 may be sandwiched between a pair of polarizing plates 1 and 8. Further, in FIG. 1, a color filter 6 is provided between the second substrate 7 and the alignment film 4. The liquid crystal display element according to the present invention may be a so-called color filter on array (COA), or may be provided with a color filter between an electrode layer including a thin film transistor and a liquid crystal layer, or the thin film transistor. A color filter may be provided between the electrode layer containing and the second substrate.

  That is, the liquid crystal display element 10 according to the present invention includes a first polarizing plate 1, a first substrate 2, an electrode layer 3 including a thin film transistor, an alignment film 4, a liquid crystal layer 5 including a liquid crystal composition, The alignment film 4, the color filter 6, the second substrate 7, and the second polarizing plate 8 are sequentially stacked.

  The first substrate 2 and the second substrate 7 can be made of a transparent material having flexibility such as glass or plastic, and one of them can be an opaque material such as silicon. The two substrates 2 and 7 are bonded together by a sealing material and a sealing material such as an epoxy thermosetting composition disposed in the peripheral region, and in order to maintain the distance between the substrates, for example, Spacer columns made of resin formed by granular spacers such as glass particles, plastic particles, alumina particles, or the photolithography method may be arranged.

  FIG. 2 is an enlarged plan view of a region surrounded by the II line of the electrode layer 3 formed on the substrate 2 in FIG. 3 is a cross-sectional view of the liquid crystal display element shown in FIG. 1 taken along the line III-III in FIG. As shown in FIG. 2, the electrode layer 3 including thin film transistors formed on the surface of the first substrate 2 includes a plurality of gate bus lines 26 for supplying scanning signals and a plurality of gate bus lines 26 for supplying display signals. Data bus lines 25 are arranged in a matrix so as to cross each other. In FIG. 2, only a pair of gate bus lines 25 and a pair of data bus lines 24 are shown.

  A unit pixel of the liquid crystal display device is formed by a region surrounded by the plurality of gate bus lines 26 and the plurality of data bus lines 25, and a pixel electrode 21 and a common electrode 22 are formed in the unit pixel. . A thin film transistor including a source electrode 27, a drain electrode 24, and a gate electrode 28 is provided in the vicinity of an intersection where the gate bus line 26 and the data bus line 25 intersect each other. The thin film transistor is connected to the pixel electrode 21 as a switch element that supplies a display signal to the pixel electrode 21. A common line 29 is provided in parallel with the gate bus line 26. The common line 29 is connected to the common electrode 22 in order to supply a common signal to the common electrode 22.

  A preferred embodiment of the structure of the thin film transistor is provided, for example, as shown in FIG. 3 so as to cover the gate electrode 11 formed on the surface of the substrate 2 and the gate electrode 11 and cover the substantially entire surface of the substrate 2. A protective film provided to cover a part of the surface of the gate insulating layer 12, the semiconductor layer 13 formed on the surface of the gate insulating layer 12 so as to face the gate electrode 11, and the semiconductor layer 17. 14, a drain electrode 16 provided so as to cover one side end of the protective layer 14 and the semiconductor layer 13 and to be in contact with the gate insulating layer 12 formed on the surface of the substrate 2, and the protection A source electrode 17 which covers the film 14 and the other side edge of the semiconductor layer 13 and is in contact with the gate insulating layer 12 formed on the surface of the substrate 2; And 16 and the source electrode 17 insulating protective layer 18 provided to cover the, the it has. An anodic oxide film (not shown) may be formed on the surface of the gate electrode 11 for reasons such as eliminating a step with the gate electrode.

  Amorphous silicon, polycrystalline polysilicon, or the like can be used for the semiconductor layer 13, but when a transparent semiconductor film such as ZnO, IGZO (In—Ga—Zn—O), or ITO is used, it is caused by light absorption. It is also preferable from the viewpoint of suppressing the adverse effect of the optical carrier and increasing the aperture ratio of the element.

  Furthermore, an ohmic contact layer 15 may be provided between the semiconductor layer 13 and the drain electrode 16 or the source electrode 17 in order to reduce the width and height of the Schottky barrier. For the ohmic contact layer, a material in which an impurity such as phosphorus such as n-type amorphous silicon or n-type polycrystalline polysilicon is added at a high concentration can be used.

  The gate bus line 26, the data bus line 25, and the common line 29 are preferably metal films, more preferably Al, Cu, Au, Ag, Cr, Ta, Ti, Mo, W, Ni, or an alloy thereof, Al or Cu The case of using the alloy wiring is particularly preferable. The insulating protective layer 18 is a layer having an insulating function, and is formed of silicon nitride, silicon dioxide, silicon oxynitride film, or the like.

  In the embodiment shown in FIGS. 2 and 3, the common electrode 22 is a flat electrode formed on almost the entire surface of the gate insulating layer 12, while the pixel electrode 21 is an insulating protective layer 18 covering the common electrode 22. It is a comb-shaped electrode formed on the top. That is, the common electrode 22 is disposed at a position closer to the first substrate 2 than the pixel electrode 21, and these electrodes are disposed so as to overlap each other via the insulating protective layer 18. The pixel electrode 21 and the common electrode 22 are formed of a transparent conductive material such as ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), or IZTO (Indium Zinc Tin Oxide). Since the pixel electrode 21 and the common electrode 22 are formed of a transparent conductive material, the area opened by the unit pixel area increases, and the aperture ratio and transmittance increase.

  In addition, the pixel electrode 21 and the common electrode 22 have an interelectrode distance (also referred to as a minimum separation distance): R between the pixel electrode 21 and the common electrode 22 in order to form a fringe electric field between the electrodes. The distance between the first substrate 2 and the second substrate 7 is smaller than G. Here, the distance between electrodes: R represents the distance in the horizontal direction on the substrate between the electrodes. FIG. 3 shows an example in which the plate-shaped common electrode 22 and the comb-shaped pixel electrode 21 overlap each other, and therefore an example in which the inter-electrode distance: R = 0 is shown, and the minimum separation distance: R is the first substrate 2. The distance between the first substrate 7 and the second substrate 7 (ie, the cell gap) is smaller than G, so that a fringe electric field E is formed. Therefore, the FFS type liquid crystal display element can use a horizontal electric field formed in a direction perpendicular to a line forming the comb shape of the pixel electrode 21 and a parabolic electric field. The electrode width of the comb-shaped portion of the pixel electrode 21: l and the width of the gap of the comb-shaped portion of the pixel electrode 21: m are such that all the liquid crystal molecules in the liquid crystal layer 5 can be driven by the generated electric field. It is preferable to form. The minimum separation distance R between the pixel electrode and the common electrode can be adjusted as the (average) film thickness of the gate insulating film 12. In addition, unlike the liquid crystal display element according to the present invention, an inter-electrode distance (also referred to as a minimum separation distance) between the pixel electrode 21 and the common electrode 22: R is different from that of the first substrate 2 and the second substrate. The distance from the substrate 7 may be larger than G (IPS method). In this case, for example, a configuration in which comb-like pixel electrodes and comb-like common electrodes are provided alternately in substantially the same plane can be cited.

  The liquid crystal display element according to the present invention preferably has an FFS mode liquid crystal display composition utilizing a fringe electric field, and the shortest distance d between the common electrode 22 and the pixel electrode 21 is such that the alignment layers 4 (between the substrates) are aligned. When the distance is shorter than the shortest separation distance D, a fringe electric field is formed between the common electrode and the pixel electrode, and the horizontal and vertical alignments of the liquid crystal molecules can be used efficiently. In the case of the FFS mode liquid crystal display element as in the preferred embodiment of the present invention, when a voltage is applied to the liquid crystal molecules arranged so that the long axis direction is parallel to the alignment direction of the alignment layer, it is common with the pixel electrode 21. An equipotential line of a parabolic electric field is formed between the electrode 22 and the upper part of the pixel electrode 21 and the common electrode 22 and is arranged along the electric field in which the major axis of the liquid crystal molecules in the liquid crystal layer 5 is formed. In particular, since the liquid crystal composition according to the present invention uses liquid crystal molecules having positive dielectric anisotropy, the major axis direction of the liquid crystal molecules is aligned along the generated electric field direction.

  The color filter 6 preferably forms a black matrix (not shown) in a portion corresponding to the thin film transistor and the storage capacitor 23 from the viewpoint of preventing light leakage.

  On the electrode layer 3 and the color filter 6, a pair of alignment films 4 that are in direct contact with the liquid crystal composition constituting the liquid crystal layer 5 and induce homogeneous alignment are provided.

  In addition, the polarizing plate 1 and the polarizing plate 8 can be adjusted so that the viewing angle and the contrast are good by adjusting the polarizing axis of each polarizing plate, and the transmission axes thereof operate in the normally black mode. In addition, it is preferable to have transmission axes perpendicular to each other. In particular, any one of the polarizing plate 1 and the polarizing plate 8 is preferably arranged so as to have a transmission axis parallel to the alignment direction of the liquid crystal molecules 30. Further, it is preferable to adjust the product of the refractive index anisotropy Δn of the liquid crystal and the cell thickness d so that the contrast is maximized. Furthermore, a retardation film for widening the viewing angle can also be used.

  EXAMPLES The present invention will be described in further detail with reference to examples below, but the present invention is not limited to these examples. Further, “%” in the compositions of the following Examples and Comparative Examples means “% by mass”.

  In the examples, the measured characteristics are as follows.

T _ni : Nematic phase-isotropic liquid phase transition temperature (° C.)
T _cn : Solid phase-nematic phase transition temperature (° C.)
Δn: Refractive index anisotropy at 20 ° C. Δε: Dielectric anisotropy at 20 ° C. η: Viscosity at 20 ° C. (mPa · s)
γ1: rotational viscosity at 20 ° C. (mPa · s)
VHR (Init): Voltage holding ratio (%) at 60 ° C. under conditions of frequency 60 Hz and applied voltage 1 V
VHR (HEAT): Voltage holding ratio (%) at 60 ° C. under the conditions of a frequency of 60 Hz and an applied voltage of 1 V measured after standing at 100 ° C. for 48 hours.
Drop mark: The drop mark of the liquid crystal display device was evaluated by the following four-step evaluation of the drop mark that appeared white when the entire surface was displayed in black.

◎: No dripping trace ○: Drip trace is acceptable but acceptable △: Drop trace is unacceptable level ×: Dripping trace is considerably poor Line afterimage: Line afterimage test of liquid crystal display element When a predetermined fixed pattern was displayed in the area for 2000 hours, the level of the linear afterimage generated at the boundary portion of the fixed pattern was visually evaluated by the following four-step evaluation.

◎: No line afterimage ○: An acceptable level even though there is a slight line afterimage △: An unacceptable level with a line afterimage ×: A considerably poor level with a line afterimage (side chain)
-F -F Fluorine atom
F- -F Fluorine atom
-n -C _n H _{2n + 1} linear alkyl group with n carbon atoms
n- C _n H _{2n + 1-} linear alkyl group with n carbon atoms
-On -OC _n H _{2n + 1} linear alkoxyl group with n carbon atoms
nO- C _n H _{2n + 1} O- Linear alkoxyl group with n carbon atoms
-V -CH = CH ₂
V- CH ₂ = CH-
-V1 -CH = CH-CH ₃
1V- CH ₃ -CH = CH-
-2V -CH ₂ -CH ₂ -CH = CH ₃
V2- CH ₃ = CH-CH ₂ -CH _2-
-2V1 -CH ₂ -CH ₂ -CH = CH-CH ₃
1V2- CH ₃ -CH = CH-CH ₂ -CH ₂
(Linking group)
-CF2O- -CF ₂ -O-
-OCF2- -O-CF _2-
-1O- -CH ₂ -O-
-O1- -O-CH _2-
(Ring structure)

(Example 1, Comparative Example 1 and Comparative Example 2)
Liquid crystal compositions LC-1 (Example 1), LC-A (Comparative Example 1) and LC-B (Comparative Example 2) were prepared. The measurement of these physical property values, the measurement of VHR (Init) and VHR (HEAT), the presence or absence of dripping marks, and the presence or absence of a line afterimage were evaluated.

  The antioxidants (St-1) and (St-2) are

It is a compound represented by these.

Significant differences were confirmed by VHR (HEAT), the presence or absence of dripping marks, and the presence or absence of a line afterimage. From these results, the liquid crystal composition LC-1 of the present invention has a liquid crystal phase in a wide temperature range, low viscosity, good solubility at low temperatures, high specific resistance and high voltage holding ratio, heat and light. In contrast, it was confirmed that a stable Δε is a positive liquid crystal composition, and a liquid crystal display device using this composition is excellent in display quality and hardly causes display defects such as dripping marks and line afterimages.
(Example 2, Example 3, Example 4, Example 5, Example 6 and Comparative Example 3)
Liquid crystal compositions LC-2 (Example 2), LC-3 (Example 3), LC-4 (Example 4), LC-5 (Example 5), LC-6 (Example) and LC-C (Comparative Example 3) was prepared. The measurement of these physical property values, the measurement of VHR (Init) and VHR (HEAT), the presence or absence of dripping marks, and the presence or absence of a line afterimage were evaluated.

  Significant differences were confirmed by VHR (HEAT), the presence or absence of dripping marks, and the presence or absence of a line afterimage. From these results, the liquid crystal compositions LC-2, LC-3, LC-4 and LC-5 of the present invention have a liquid crystal phase in a wide temperature range, low viscosity, good solubility at low temperatures, A liquid crystal composition having a high specific resistance and a high voltage holding ratio and a positive Δε that is stable to heat and light. It was confirmed that it was difficult to occur.

DESCRIPTION OF SYMBOLS 1,8 Polarizing plate 2 First substrate 3 Electrode layer 4 Alignment film 5 Liquid crystal layer 6 Color filter 6G Color filter green 6R Color filter red 7 Second substrate 11 Gate electrode 12 Gate insulating film 13 Semiconductor layer 14 Insulating layer 15 Ohmic Contact layer 16 Drain electrode 17 Source electrode 18 Insulating protective layer 21 Pixel electrode 22 Common electrode 23 Storage capacitor 24 Drain electrode 25 Data bus line 27 Source bus line 29 Common line 30 Buffer layer

Claims (6)

As a liquid crystal compound having a positive dielectric anisotropy containing 1% or more of a liquid crystal compound having a positive dielectric anisotropy having an absolute value of 4 or more, and having an absolute value of 4 or more, General formula (N1):

(In the general formula (N1), R ⁿ¹ represents an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, and one or non-adjacent two or more —CH in the group. ₂ - each independently, -C≡C -, - O -, - CO -, - COO- or may be substituted by -OCO-, 1 one or non-adjacent two or more in the group Each hydrogen atom may be independently substituted with a fluorine atom,
Ring N ¹ is a 1,4-cyclohexylene group (one or two or more non-adjacent —CH ₂ — in the group may be substituted by —O— or —S—) or 1, Represents a 4-phenylene group (one or two or more non-adjacent —CH═ in the group may be substituted by —N═), and each hydrogen atom in the group independently represents a cyano group. , May be substituted with a fluorine atom,
Z ⁿ¹ is a single bond, —CH ₂ CH ₂ —, — (CH ₂ ) ₄ —, —OCH ₂ —, —CH ₂ O—, —OCF ₂ —, —CF ₂ O—, —CH ₂ CH ₂ CF _{2 represents} O-, -COO-, -OCO- or -C≡C-
Z ⁿ² represents —OCH ₂ —, —CH ₂ O—, —OCF ₂ — or —CF ₂ O—,
n ⁿ¹ each independently represents an integer of 0 to 4, and when n ⁿ¹ is 2 or more, ring N ¹ may be the same or different, and when n ⁿ¹ is 1 or more, Z ⁿ¹ is Can be the same or different,
X ⁿ¹ , X ⁿ² , X ⁿ³ , X ⁿ⁴ and X ⁿ⁵ each independently represent a hydrogen atom or a fluorine atom,
Y ⁿ¹ each independently represents a fluorine atom, a cyano group, a trifluoromethyl group, a fluoromethoxy group, a difluoromethoxy group, a trifluoromethoxy group or a 2,2,2-trifluoroethyl group, A trifluoromethyl group, a fluoromethoxy group, a difluoromethoxy group or a trifluoromethoxy group; )
One or more compounds represented by:
Formula (II)

(In the general formula (II), M represents an alkylene group having 2 to 15 carbon atoms) , and a liquid crystal composition having a positive dielectric anisotropy. The compound represented by the general formula (II) is represented by the general formula (II-a)

In a compound represented by a liquid crystal composition according to claim 1. A polymerizable compound 1 or more, according to claim 1 or a liquid crystal composition according to 2. A first substrate having a common electrode made of a transparent conductive material; a second substrate having a pixel electrode made of a transparent conductive material; and a thin film transistor for controlling the pixel electrode provided in each pixel; A liquid crystal display element having a liquid crystal composition sandwiched between a substrate and a second substrate, wherein the alignment of liquid crystal molecules in the liquid crystal composition when no voltage is applied is substantially parallel or substantially perpendicular to the substrate. A liquid crystal display device using the nematic liquid crystal composition according to any one of claims 1 to 3 as the liquid crystal composition. A liquid crystal display device produced by using a liquid crystal composition containing at least one polymerizable compound according to claim 3 and polymerizing the polymerizable compound contained in the liquid crystal composition with or without application of a voltage. . A liquid crystal display device containing the liquid crystal composition according to the polymerizable compound to polymer and claim 1 or 2 was polymerized.

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